Impurity-limited quantum transport variability in magnetic tunnel junctions

TL;DR

This study uses first-principles calculations to analyze how impurities affect the variability of quantum tunneling and device performance in magnetic tunnel junctions, providing insights for improving reliability in spintronic devices.

Contribution

It offers a detailed first-principles analysis of impurity-induced variability in magnetic tunnel junctions and predicts N-doping as a means to enhance device performance.

Findings

N-doped MgO improves MTJ performance

Impurities cause significant variability in tunneling currents

First-principles calculations predict device reliability trends

Abstract

We report an extensive first-principles investigation of impurity-induced device-to-device variability of spin-polarized quantum tunneling through Fe/MgO/Fe magnetic tunnel junctions (MTJ). In particular, we calculated the tunnel magnetoresistance ratio (TMR) and the average values and variances of the currents and spin transfer torque (STT) of an interfacially doped Fe/MgO/Fe MTJ. Further, we predicted that N-doped MgO can improve the performance of a doped Fe/MgO/Fe MTJ. Our first-principles calculations of the fluctuations of the on/off currents and STT provide vital information for future predictions of the long-term reliability of spintronic devices, which is imperative for high-volume production.